Deck 27: Weldability of Metals

Question 1

In the steel classification system, the last two digits refer to ____.

A) the basic type of steel
B) the range of carbon content
C) the melting point
D) the basic alloy group

Answer 1

B

Question 2

For steels containing more than ____ % carbon, preheating and subsequent heat treatment generally are required.

A) 0.30
B) 0.40
C) 30
D) 40

Answer 2

B

Question 3

High carbon steels usually have a carbon content of ____ %.

A) 0.30
B) 0.30 to 0.50
C) 0.50 to 0.90
D) 30 to 90

Answer 3

C

Question 4

The carbon content of high manganese steel is ____ %.

A) 0.01 to 0.14
B) 0.30 to 0.50
C) 0.50 to 0.90
D) 1 to 1.4

Question 5

Steel is classified according to ____.

A) melting point
B) ductility
C) basic chemical composition
D) hardness

Question 6

The strength of ____ stainless steels is the result of a special heat treatment.

A) ferritic
B) austenitic
C) martensitic
D) precipitation hardening

Question 7

If the chromium-nickel content of a stainless steel is referred to as 25-12, then it contains ____.

A) 25 percent nickel and 12 percent chromium
B) 75 percent chromium and 8 percent nickel
C) 25 percent chromium and 12 percent nickel
D) 75 percent nickel and 8 percent chromium

Question 8

Most welding processes produce a(n) ____ in which the metals are heated over a range of temperatures.

A) thermal cycle
B) fusion cycle
C) interpass temperature
D) phase change

Question 9

In both steel classification systems, the first number often, but not always, refers to ____.

A) the most appropriate type of welding
B) the basic type of steel
C) the melting point
D) the carbon content

Question 10

Low carbon steel has a carbon content of less than ____ %.

A) 0.15
B) 0.30
C) 0.50
D) 30

Question 11

To improve weldability in stainless steel, the carbon content should not be more than ____ %.

A) 0.03
B) 0.30
C) 3.0
D) 30.0

Question 12

High manganese steel contains ____ % or more manganese.

A) 0.12
B) 0.22
C) 12
D) 22

Question 13

____ stainless steels are used for ornamental or decorative applications such as architectural trim, and tend to be brittle.

A) Ferritic
B) Austenitic
C) Martensitic
D) Precipitation hardening

Question 14

Medium carbon steel has ____ % carbon content.

A) 0.30
B) 0.30 to 0.50
C) 30
D) 30 to 50

Question 15

The ability of carbon steel to be welded is a function of ____.

A) the melting point
B) the ductility
C) the welding process
D) the carbon content

Question 16

Chromium carbides form when the metal is between ____ Fahrenheit.

A) 200° and 500º
B) 500° and 800º
C) 800° and 1500°
D) 1500° and 2000°

Question 17

In the AISI system, the letter ____ indicates basic open-hearth or electric furnace steel and basic oxygen furnace steel.

A) C
B) E
C) F
D) O

Question 18

____ stainless steels are used in applications requiring both wear resistance and corrosion resistance, such as surgical knives and razor blades.

A) Ferritic
B) Austenitic
C) Martensitic
D) Precipitation hardening

Question 19

When welding tool steel using the gas welding method, the rods selected for welding repairs should have ____.

A) a carbon content matching the base metal
B) a much higher carbon content than the base metal
C) a slightly higher carbon content than the base metal
D) a much lower carbon content than the base metal

Question 20

Which of the following is a stainless steel alloy group?

A) Chromium alloy
B) Nickel chromium
C) Manganese alloy
D) Ferritic

Question 21

​What is the major purpose of pre- and post-heating cast iron for welding?

A) ​To allow the weld to fuse deeper into the joint.
B) ​To control the rate of temperature change.
C) ​To reduce the carbon content in the casting around the weld which makes it less brittle.
D) ​It helps the weld metal flow more evenly into the crack.

Question 22

____________________ steel is used for wear resistance in applications involving impact, such as power shovels, rock crushers, mine equipment, and augers.

Question 23

​Why must some castings be repaired without pre- and post-heating?

A) ​They are large or have to be repaired in place.
B) ​They are made of a type of cast iron that cannot be preheated because it is too soft.
C) ​It would damage the paint job on the part.
D) ​Cast iron repairs always require pre- and post-heating.

Question 24

​Why are fluxing materials used for welding?

A) ​To produce a shinier surface on the weld.
B) ​Because some metals are reactive to the atmosphere when heated.
C) ​It is a way to help control the heat input to the base plate.
D) ​To insure 100% joint penetration on V-grooved joints.

Question 25

Pure aluminum melts at ____ Fahrenheit.

A) 1200°
B) 1500°
C) 1800°
D) 2200°

Question 26

All five types of cast iron have carbon contents ranging from ____ %.

A) 0.30 to 0.50
B) 0.50 to 0.90
C) 1.7 to 2
D) 1.7 to 4

Question 27

​Chromium-molybdenum steel welds have a tensile strength of ____ psi.

A) ​10,000 to 25,000
B) ​30,000 to 45,000
C) ​60,000 to 80,000
D) ​90,000 to 100,000

Question 28

____________________ steels contain specified larger proportions of alloying elements.

Question 29

​Why must metal that is below 70°F (20°C) be preheated before welding?

A) ​If the metal is too cold, you cannot get a weld pool established.
B) ​Because the cold metal quenches the weld.
C) ​The arc on cold metal is not stable, and it will wander around the surface making it hard to keep the weld going along the joint.
D) ​The hot metal on the cold plate will not stick, it just bounces off.

Question 30

​Why must all surface contamination be removed before making a repair weld?

A) ​To prevent injuring your health from exposure to materials released during welding.
B) ​Some chemicals contaminations can be completely safe until they are exposed to the welding.
C) ​The smoke or fumes contamination produce can be an irritant to the skin or eyes.
D) ​All of the above

Question 31

Steels alloyed with carbon and a low concentration of silicon and manganese are known as ____________________ steels.

Question 32

​Which type of cast iron undergoes a transformation as a result of a long heat-treating process to reduce hardness?

A) ​gray
B) ​white
C) ​malleable
D) ​nodular

Question 33

​What type of flux is required to gas weld cast iron?

A) ​C-flux
B) ​Acid flux
C) ​High temperature cast iron welding flux.
D) ​No flux is required to gas weld cast iron.

Question 34

​____ stainless steels tend to be brittle unless specially deoxidized.

A) ​Ferritic
B) ​Austenitic
C) ​Martensitic
D) ​Precipitation hardening

Question 35

____________________ steel has a carbon content of 0.8% to 1.5%, making it very difficult to weld.

Question 36

The weight of magnesium is ____ that of steel, and ____ that of aluminum.

A) 1/4, 1/2
B) 1/4, 2/3
C) 1/3, 2/3
D) 1/2, 2/3

Question 37

The term ____________________ describes the ease with which a metal can be welded properly.

Question 38

​Which type of cast iron is the most widely used?

A) ​gray
B) ​white
C) ​malleable
D) ​alloy

Question 39

​Which of the following is not a common defect if the wrong filler metal is selected for a weld?

A) ​porosity
B) ​cracks
C) ​underfill
D) ​Filler metal just will not stick.

Question 40

​What is the most common preheating temperature range for most steels?

A) ​250°F to 400°F (120°C to 200°C)
B) ​50°F to 100°F (10°C to 37°C)
C) ​350°F to 650°F (170°C to 340°C)
D) ​65°F to 145°F (18°C to 62°C)

Question 41

Two of the most important properties of the nonferrous metal ____________________ are its extremely high strength-to-weight ratio (in alloy form) and its generally excellent corrosion resistance.

Question 42

____________________ stainless steels contain almost no nickel and are cheaper than austenitic steels.

Question 43

Explain the meaning of the numbers in the SAE and AISI classification systems.

Question 44

Describe the two recommended procedures to be observed for arc welding tool steel.

Question 45

The most widely used stainless steels are the ____________________ types.

Question 46

How can cracks in martensite be prevented?

Question 47

____________________ steels are used because of increasing demand for high strength and less weight.

Question 48

Chromium and carbon combine to form ____________________.

Question 49

Explain why a part must be cleaned before repair or maintenance welding can be performed.

Question 50

Summarize the uses of chromium-molybdenum steel, including applications it is used for, processes used to weld it, and its tensile strength.